1,720,961 research outputs found
An Investigation on the Possible Application Areas of Low-Cost PM Sensors for Air Quality Monitoring
Get PDFIn recent years, the availability on the market of low-cost sensors (LCSs) and low-cost monitors (LCMs) for air quality monitoring has attracted the interest of scientists, communities, and professionals. Although the scientific community has raised concerns about their data quality, they are still considered a possible alternative to regulatory monitoring stations due to their cheapness, compactness, and lack of maintenance costs. Several studies have performed independent evaluations to investigate their performance, but a comparison of the results is difficult due to the different test conditions and metrics adopted. The U.S. Environmental Protection Agency (EPA) tried to provide a tool for assessing the possible uses of LCSs or LCMs by publishing guidelines to assign suitable application areas for each of them on the basis of the mean normalized bias (MNB) and coefficient of variance (CV) indicators. Until today, very few studies have analyzed LCS performance by referring to the EPA guidelines. This research aimed to understand the performance and the possible application areas of two PM sensor models (PMS5003 and SPS30) on the basis of the EPA guidelines. We computed the R2, RMSE, MAE, MNB, CV, and other performance indicators and found that the coefficient of determination (R2) ranged from 0.55 to 0.61, while the root mean squared error (RMSE) ranged from 11.02 µg/m3 to 12.09 µg/m3. Moreover, the application of a correction factor to include the humidity effect produced an improvement in the performance of the PMS5003 sensor models. We also found that, based on the MNB and CV values, the EPA guidelines assigned the SPS30 sensors to the “informal information about the presence of the pollutant” application area (Tier I), while PMS5003 sensors were assigned to the “supplemental monitoring of regulatory networks” area (Tier III). Although the usefulness of the EPA guidelines is acknowledged, it appears that improvements are necessary to increase their effectiveness
Rete di monitoraggio della qualità dell'aria. Infrastrutture e realizzazione
No full textQuesto documento presenta le attività che hanno portato alla realizzazione di un’infrastruttura per il monitoraggio ambientale che si basa su dispositivi per il rilevamento di inquinanti atmosferici gassosi, polveri sottili, e parametri ambientali, utili a definire lo stato di qualità dell’aria in aree urbane. Tale infrastruttura permette un controllo in tempo “quasi” reale degli inquinanti atmosferici monitorati e basa il proprio funzionamento sui dispositivi multisensoriali AIRBOX, interamente prodotti all’interno del Laboratorio Test Sensori del Centro Ricerche ENEA di Brindisi, che ne costituiscono gli elementi cognitivi dispiegati sul territorio e che formano una rete wireless per la raccolta dei dati di interesse. I dati di misura forniti dagli AIRBOX vengono filtrati, aggregati ed elaborati secondo modalità che possono variare in funzione dell’utenza cui sono destinati: si passa dalla trasmissione dati secondo protocolli di comunicazione protetti, contemplati per un’utenza tecnico/scientifica, alla più intuitiva interfaccia web che consente una più immediata consultazione dei dati anche da parte di utenze meno esperte. Tale infrastruttura si presta ad un utilizzo su più fronti che possono variare dal semplice monitoraggio statistico della presenza di inquinanti, alla produzione di dati per lo sviluppo e la verifica di modellistica ambientale, al non meno importante supporto decisionale per gli organi che quotidianamente si interfacciano con problematiche ed aspetti connessi alla qualità dell’aria ed al benessere generale. L’infrastruttura è stata fortemente voluta ed incentivata in contesto “smart cities” per un’applicazione diretta nel Progetto RES-NOVAE: in tale occasione è stata dispiegata una rete di monitoraggio sull’area metropolitana di Bari con il posizionamento di AIRBOX su strutture fisse e mezzi mobili. La rete di monitoraggio ha visto il dispiego dei nodi durante il secondo semestre del 2015 ed è operativa al momento della stesura di questo documento.This paper deals with the implementation of a research infrastructure as a sensor network for urban air quality monitoring. It is based on distributed devices (sensor-nodes) for measuring air pollutants such as toxic gases and particulate matters, including other environmental parameters, to understand the air quality level in the urban areas. This tool allows to achieve a nearly real-time tracking of the atmospheric pollutants concentration by multi-parametric sensor-systems, called AIRBOX, completely designed and fabricated in our Sensor Test Laboratory at ENEA Research Center in Brindisi. These sensor-systems (sensor-nodes) have been deployed over the targeted area to form a wireless network for gathering data of environmental interest. Measurements provided by sensor-nodes (AIRBOX) are filtered, collected and processed covering a wide spectrum of use: from scientific purposes, with data delivered by protected communications protocols for science and technology community, to environmental informatics services with friendly webuser interfaces at easy reading for not-skilled users (citizens). This sensors network can be useful for several purposes: monitoring of the targeted air-pollutant levels, delivering data for chemical weather forecasting and air quality modelling, providing information to support the decision-making process of the local authorities devoted to the public health and related to air quality monitoring. The sensors-network described in this paper has been strongly pursued in the “smart cities” context
and demonstrated in the “RES-NOVAE” national project. To achieve this goal, a wireless network composed by AIRBOX sensor-systems has been deployed in the urban area of the Bari city for air quality monitoring. The sensor-nodes have been placed both in stationary sites and on mobile vehicles like public buses. This monitoring network has been deployed on July 2015 and at the current time we are writing this paper is still working
Air Quality Monitoring in a Near-City Industrial Zone by Low-Cost Sensor Technologies: A Case Study
Get PDFUrban industrial areas are often a matter of concern due to the emission of air pollutants that may affect the air quality of adjacent cities. Aerosol pollutants are monitored by governmental agencies that employ regulatory monitoring stations which are very accurate, but also very expensive, bulky, and demanding in terms of maintenance. For this reason, it often happens that the monitoring of the air quality in large areas is covered by few stations. This situation can lead to the building of air pollutant maps with low spatio-temporal resolution. An appealing way to address this issue is represented by low-cost miniaturized gas sensors (LCSs) employed in low-cost air quality monitors (LCMs). Despite the various and unquestionable points of strength characterizing these devices, the scientific community has raised several warnings about the accuracy of their measurements and issued many caveats regarding their use. In this study, a new LCM model designed and implemented in our laboratories was used to measure the NO2 and PM concentrations in the industrial area of Brindisi (Italy). Data gathered by the LCM were compared with reference instrumentations for a rigorous analysis of the performance achievable through these low-cost technologies in this particular case
Field Performance Evaluation of Air Quality Low-Cost Sensors Deployed in a Near-City Space-Airport
Get PDFAir pollution is a current problem for the environment and public health. Its impact needs to be monitored in urban agglomerates and critical hot spots such as airports. Green aviation with low air emissions is a sustainable goal for the future. The air pollutants are monitored by governmental agencies that employ regulatory monitoring stations, which are very accurate but also very expensive, bulky, and maintenance demands. On the contrary, low-cost sensor systems can offer a proper solution to cover large areas at high spatial-temporal resolution. However, the low-cost air quality sensors are less accurate than reference analyzers operating in the regulatory stations. To enhance the sensor accuracy, field calibration, and data correction with reference instrumentation is a valid strategy to improve sensor data quality. In this study, a sensor system with a selected set of air quality gas sensors (NO2, O3) and particulate matter (PM10, PM2.5) has been developed and deployed in a near-city space-airport at Grottaglie (Southern Italy) to perform measurements in a period of 4 months, from October 2021 to February 2022. The sensor units installed in the Airbox system used for this measurements campaign are the GS+4NO2 (DD Scientific) for NO2 measurements, the O3-3E1F (City Technology, Sensoric) for O3 measurements, and the NextPM (Tera Sensor) for PM10 and PM2.5 measurements. Data gathered by the low-cost air quality sensors have been compared to reference instrumentations both co-located (ca. 1 m distance) together with low-cost sensors (PM10, R2 > 0.87; PM2.5, R2 > 0.50) and a distributed regulatory network of 14 environmental stations operating in the local area around space-airport at a distance ranging from 3 to 26 km
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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